Dealey Plaza is a patch of downtown Dallas that stands as a historic marker of one of the most tragic and jarring events of the 20th century: the assassination of President John F. Kennedy. The sixth floor of the schoolbook depository building where assassin Lee Harvey Oswald fired three shots that struck Kennedy and Texas Gov. John Connally is now a museum dedicated to preserving the history and artifacts of that infamous day and using education, discussion and community outreach in the hopes that it won’t be repeated…